| AC | = Atrial Contraction (Systole) (Phase 1) |
|---|---|
| IVC | = Isovolumic Ventricular Contraction (Systole) (Phase 2) |
| Ejection | = Ventricular Ejection (Phase 3) |
| IVR | = Isovolumic Ventricular Relaxation (Diastole ) (Phase 4) |
| RF | = Rapid Ventricular Filling (Phase 5) |
| Diastasis | = Diastasis ("resting phase") (Phase 6) |
The lower case letters on the left heart pressure curve correspond to waves appearing in the venous pulse.
| a | = a wave (caused by contraction of atrium) |
|---|---|
| c | = c wave (caused by contraction of the ventricles) |
| x | = x descent (caused by pulling of contracted right ventricle on tricuspid valve) |
| v | = v wave (caused by venous return filling the large veins) |
| y | = y descent (caused by blood flowing into the right atrium |